1. Field of the Invention
The present invention relates to a light emitting diode light bar structure, and particularly to a light emitting diode light bar structure having heat dissipation function.
2. Related Art
Liquid crystal display (LCD) panels are now widely used in electronic products which have growing potential such as monitors, notebooks, digital cameras, projectors, and so on. After producing a glass base, LCD panel manufacturers firstly assemble and package up the glass base with color filters, then fill liquid crystals therein, and further assemble with a backlight module, driving integrated circuits (IC), and control circuit boards, etc., to cooperatively produce a LCD module so as to sell it to downstream manufactures of notebooks or LCD monitors.
The backlight module is one of key components of the LCD panel. Because liquid crystals do not emit light directly themselves, the function of the backlight module is to provide sufficient brightness and uniform emitting light source in order to normally display images. The backlight module is mainly assembled with components including light sources, lamp covers, reflector sheets, light guide plates, diffuser sheets, brightness enhancement films and frames, etc.
Generally speaking, backlight modules have been developed based on size requirements into a type of edge lighting structures and another type of bottom lighting structures, which are categorized by locations of lamp tubes thereof. Wherein, a light source of the type of edge lighting structures is a single light source placed aside, and a light source of the type of bottom lighting structures is placed right beneath. The lamp tubes of the backlight modules must be featured with high brightness and a long lifespan, etc. They currently include cold cathode fluorescent lamps (CCFL), hot cathode fluorescent lamps, light emitting diodes (LED) and electroluminescence (EL), etc.
Among them, the CCFL has characters of high luminance, high efficiency, a long lifespan, and high color rendering, etc. Besides, it is much easier to be assembled with light reflection components to form a thin-sheet lighting device due to its cylinder shape. Therefore, using the CCFL as main backlight sources was once a main trend for making backlight modules. However, the CCFL is gradually eliminated by the present trend of soaring environmental awareness today due to its filled content of mercury vapors. Since using LED as backlight sources has an advantage of energy saving and environmental protection over the CCFL, it becomes a trend in backlight development to replace the CCFL by the LED. A lighting structure of the LED is generally called as a light bar in practice.
Referring to FIG. 1, FIG. 1 is a perspective view showing a structure of a currently existing LED light bar. As shown in FIG. 1, a LED light bar structure 90 includes a circuit board 91 of a substantially long strap shape and a plurality of LEDs 92. The plurality of LEDs 92 are arranged on an upper surface of the circuit board 91 and fixed thereon through a plurality of solder points 93 to be electrically connected with the circuit board 91. The LED light bar structure 90 is capable of simulating lighting effect of the CCFL light source adopted by conventional backlight modules. For either edge lighting backlight module structures or bottom lighting backlight module structures, the LED light bar 90 can be installed directly to an original location of the CCFL to replace illumination of the CCFL. Although using LEDs as the backlight source has advantages of lightness and thinness, environmental protection, electricity saving, and so on, the aforementioned existing LED light bar still has a few problems:                (1) LEDs have much complicated processing technology. Currently, LEDs are fixed onto printed circuit boards (PCBs) through soldering, and therefore its processing is much complex.        (2) Heat dissipation of LED light bar is much difficult. Since it is not easy to perform natural convection inside backlight modules, generated heat of LEDs can only be dissipated indirectly through conduction of the circuit board 91. As a result, LED light bars usually have such problem of difficult heat dissipation.        